Drawbench



Feb. 20, 1940. M. scHuNcK 2,190,889

DRAWBENCH Filed Aug. 26, 1937 55 sheets-sheet 1 35 M 7I A l-IEII Q) a s?,Q Sk

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M. SCHUNCK Feb. 20, 1940.

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Patented Feb. 2o, 1940 f UNITED STATES PATENT OFFICE DRAWBENCH Main,Germany Application August 26, 1937, Serial No. 161,153 In GermanyAugust 28, 1936 8 Claims.

` The invention relates to a drawbench and has `for its object a machineof this kind distinguishing itself by simple design and high output. Av

special object of the invention is to provide a l drawbeneh with a chainrunning in a horizontal plane round a frame formed in the shape of anI-(double T).

A second object ofthe invention is to provide a drawbench thatautomatically throws the 1 nished pieces from the bench on to atransporttruck.

A third object of the invention consists in providing a chain drawbenchwith a chain alternately movable in opposite directions and capable ofalso drawing tubes over a mandrel.l

Other objects of the invention and the advantages resulting therefrommay be seen from the following description of the invention.

The invention is shown in the drawings ac- 9 companying thisspecification in which Figure l is a side elevational view of the benchaccording to the invention,

Figure 2 a plan view and Figure 3 a cross sectional elevation on linesFigure 4 is a side elevational view partially in section of a specialtype of the drawbench for drawing tubes over the mandrel.

In the drawings 2 represents the vertical benchbedding mounted as usualon supports I. 'I'hebedding is formed in the shape of a girder having amiddle rib with guides atthe top and at the bottom. The drawings showthe middle-rib in the shape of a frame of box section. It is f advisableto give the latter approximately the breadth of the diameter of thedriving chainwheel. 5 is the chain running on both sides in the plane ofthe central section of the I-shaped4 bench-bedding. The guides 6 and 1are there i to guide it. 'I'he chain is driven by the chainwheel 3,while 4 represents a. pulley around which the chain can be reversed inits direction of movement, and through which the chain can also bere-stretched, should it have slackened considerably after working a longtime. The guides 8 and 1 are formed preferably in the shape of Z-prolesand riveted to the frame of the benchbedding. 'I'hey protect thevertically driven chain' from falling and sagging. On the side of the Idrivethat is to say before the chain reaches the pulley 3-there are aset of tension-pulleys mounted on each side. They consist of stationaryguide pulleys 8 and 9 and the tension pulleys II and I2, each of thembeing movable in the .i guides I0 transversely to the chain. Through a(o1. eos-7) compression-spring I3 the pulleys Il and I2 push the chainoutwards, thus giving it a moderate preliminary tension.. If the drawingoperation is carried out by the right hand chain, then thetension-'pulley' II is pressed down into the 5 bench by the straightenedchain, while the tension pulley I2 moves outwardly and pushed away orrestretches the surplus of chain running off the chain-pinion. If thetension-pulleys stretching the chain are properly adjusted there are no10 chain troubles to be expected on any part of the bench. lOn thecontrary, the chain will always smoothly run on to the chain-wheel. Thedriving chain-wheel 3 and reversing pulley 4 are mounted on verticalaxles I4 and driven by a motor I5 l5 with the aid of gearing I6 and apair of bevelwheels I1.

The chain moves the two work-gripper carriages I8 and I9, which areprovided with the customary drawing-jaws or grippers and 2l Z0 forseizing the drawing-end of the work-piece. The carriages are guided bymeans of the pulleys 22 on the middle-rib of the bench-bedding. Therebythey are prevented from sliding oi the rib, partly by the upper plate 23and the lower 25 plate 24, partly by the guides 25, 26, 21 or 28. TheWork-gripper carriages are firmly coupled to the chain by means of thecams 28 and 30, note Fig. 3, catching into the chain-links. i These cams by running off the chain uncouple themselves easily at the end of thebench. In this simple way a clogging of the chain is made impossible.For coupling in again, it is only necessary tol push in the carriage byhand.

The middle axis of the drawing-operation, in 85 which the work-grippersor drawing-jaws 2Q or 2|V lie, can-according to this invention-beadjusted in such a. way that it may protrude a little over the outeredge of the lower guides 21- or 28. Consequently the pieces after beingdrawn can automatically fall into the transport-truck 3| or 32.

At the end of the bench-bedding a cross member 33 is xed, adjacent towhich the'die-holders 34 and 35 are iixed which hold the dies and finto45 which the latter are inserted. The disposition of these parts and themode of fastening them is done in the usual way,1 need not go intodetails. On the side of the dies the necessary controldevices areprovided for. By means of them, the motor can be controlled both ways tothe eiect that the chain can also move in either direction. Thiscontrol-mechanism being known to the expert, we may pass over itsconstructional de tails.

'Ihe adjustable reversing ipulley 4 gets its ten' sion from the screwsI1 and 38 and by inserting A is put into a gripping device, consistingof a split inserted noz'zle 42 adjustable by means'of a handwheel I3. Inits closed position the gripping mechanism clasps the mandrel-head 44 ina notch and holds it fast during the drawing operation. When it isopened the bloomor lump-tube Il can be put through the opening over themandrel and the die 45 can be put on the latter, While, the drawingoperation being terminated, thenished tube can be slipped oi. `On theother side Vthe f" mandrel is bedded in the grippingdevice 46, which isfixed on the transverse member 4l; The mandrel is supported by thepulleys 48, fixed to the .rocking-lever 49. According toithis method ofltubejrawing, the' gripper-carriage .50 is of a dfferent construction.Instead of. closed 'jaws' the i carriages v.are provided with an opening5I,

through which the central-axis of the mandrel passes. T'his opening iswide enough to let the die through. The carriages are provided 'withdevices 52 which hold ythe diefast during the 'drawing-operation andvwith flaps 53 for slipping the tube from the mandrel during the reversemovement of the carriage. The connection of the carriage with the chainis identical with the one in use ,in drawing through /dies-fas.described before. The flaps 52, lwhiclrare fitted to' hold the diesfast, or the vslipping off; device 53, are"`disposed in such' a way asto act upon the mandrel'twhile they are in operative position, but tooffer passage by snapping open whilst they are not in action. For thatpurpose.' they/are movably mounted on bolts 54' and 55 on the carriages.The rollers 56 or 51, equally mounted in the carriage, immediatelyloo'sen the tubes on the mandrel as soon as the drawing operation isfinished. To give `free passage, these rollers can'be i opened bylifting the flappivoted supporting armsi-j 'The bench (forinstance Whiledrawing .bars

through the dies) works as follows according to the invention.

loaded with draw-ware is as usual standing on the service side of thebench. On the left4 and right sides ofthe bench are thetransport-,trucks waiting for the finished articles. 'Ihe end of aworkpiece, for instance of aba'r, being put (on the left side -ofthebench) through the die into the jaws of the gripper-carriage, thelatter is coupled in and made to run forward, that is to say to draw.During the forward-movement of this gripper-carriage and thecorresponding back- Ward-novement of the gripper-carriage on" .the rightside of the bench, the right side of the bench is already chargedor fedwith a new. workpiece. The work-piece'on the leftside having' passed thedie, falls automatically into the transport-truck without any additionalmanipulation or help given bythe operator. At this moment, whilst thegripping carriage is stationary on the right side of the bench at theworking stand, the driving motor is reversed and the gripping carriageof the right vside of the bench' is coupled Seen by the operator thetransport-truck in. Thus a drawing operation is started on this side,while the 'gripper carriage of the left side is running back. Thedrawing-operation being iinished on the right side and the drawnwork-piece having fallen in the transport-truck, the motor orthe'direction of the chain-drive is reversed,

' whereupon (the left side gripper-carriage being coupled in again)another drawing operation is performed here, while the right-sidegripper carriage runs back empty. As shown the drawingoperation isperformed now by the right'and now by the left chain portion, for whichpurpose only the direction of the chain-drive must be reversed everytime. The operator of the bench may remain'standing at the head of thebench all the time only coupling and charging or feeding the `sides ofthe bench with draw-ware. vIt is easily understood that by this mode ofworking the output is considerably increasedjthe staff reduced and theproduction cost considerably lessened.

This working method offers many advantages. On the ,one hand the (benchworks as a double bench with only one chain running. whereby the costsof the plant are reduced. On the other hand there is less light runningand considerably less staff needed, as the throwing out ofthe finishedwork-pieces is automatically performed.

While drawing tubes over a mandrel the working method is as follows:

First insert the mandrel, then draw a bloomor lump-tube over it throughthe opened gripping device, 'fix the mandrel rmly and move the draw-.-ing`device over the fixed mandrel by means of the carriage, which isprovided with catches.. A

step or offset 60 in the mandrel prevents in the usual way the tube frombeing taken'along.

`lWhile on one side the drawing and simultaneously.. rthe loosening isgoing on, the stripping oif takes' place on the other side not shown inFig. 4. Here also the bench works'as a. double-bench offering theadvantage of increased output and reduced staff. A special advantage isoffered by the drawing of tubes over themandrel'on the drawbenchaccording to the invention, if more than the usual onedrawing-operation, is to beperformed on the same mandrelv over the tubewithout exchanging the mandrel. .If severalA drawings are to be made.successively on the same mandrel, then at the beginning of the drawingoperation instead of one die, several dies of gradually diminishingdiameter are put on the mandrel. The first die placed on the mandrel is'of course thevlargest, and is connected to the carriage. Thecarriage isthen run the length of the mandrel and one draw is thus made on thetube. Before the carriage is returned, the first die is disconnected,so` that the carriage alone returns to the starting point. The seconddie is then connected to the 'carriage and a second draw is made.Successive drawings are likewise made until the tube hasI reached thedesired size. One time the right carriage is drawing, while the left isrunning'backwards and the other time the left isldrawingwhile` the rightis running backwards. Because the reversemovement on one side coincides`with the forward-movement on the other, the light runningperiods andthereby the production-costs are con-- sliderably reduced.` V

I claim: 9'

l. A drawben'ch comprising abench-bedding having vertical sides, a chainextending adja- `cent said sides, at least one .gripping carriage,

means for mounting "and guiding said carriage along at least one of saidvertical sides to carry means for coupling saidcarriage to said chain,

a work piece in a plane outside of and parallel to said sides, and meansdriving said chain alternately in opposite directions. i

2.. A drawbench comprising a bench-beddingframe in the form of an I.' achain .means for mounting and guiding said chain substantially midway ofand on opposite sides of said I, at least one gripping-carriage, meansto couple the chain on to said gripping carriage,adrivingchain-wheelwith vertical driving axle, a pulley with vertical axle for the chain,and means for driving the chain in both directions. l

3. A drawbench comprising a bench-bedding consisting of a vertical'middlerib, guides mounted on both sides of said middle-rib, a continuouschain supported by these guides on both sides of the middle-rib. twogripping carriages moved by means of the chain on b'oth sides of saidmiddle-rib, devices to couple the gripping carriages onto the chain, adrive chain-wheel with vertical driving axle for the chain and means fordriving the chain in both directions.

4. A drawbench comprising a bench-bedding having a vertical middle-ribandl plates protruding onl both sides over the middle-rib at the top andat the bottom, at least one die mounted on one end of the said benchbedding, a continuous chain supported about both sides of saidmiddle-rib,jat least one gripping carriage moved by the chain, means togrip the articlesto be drawn, said means being moimted on saidgripping-carriage in such a way that the projection oi the connectinglinesfrom these means to the dies falls outside the plates, that arefastened underneath to the said middle-rib, devices to couple thegripping-carriages on the chain, a driving chain-wheel with verticaldriving axle, a reversing-pulley with vertical axle for the chain andmeans for driving the chain in both direc- 5. A drawbench comprising abench-bedding- !rame in the shape of a sole plate frame of box section,a chain mountedvertically and substantially midway of both sides of saidframe, gripping-carriages running on the side walls oi said frame, meansto couple said gripping-carriages on to the chain, a drive chain-wheel,a pulley, said driving chain-wheel and said pulley having a diametercorresponding approximately to the breadth of said frame, and means fordriving the chain in both directions.

6. A drawbench comprising a bench-beddingframe in the shape of a soleplate frame of box section, a continuous chain supported about bothsides of said frame, gripping carriages mounted for movement by saidchain, mea-ns for driving this chain in alternate directions, elasticchain stretching devices for restretching the non-drawing portion of thechain by means of deviation, but allowing the drawing portion to runthrough in a straight line from said driving means to a grippingcarriage.

7. A drawbench according to claim 6 comprising sets of tensionandguide-pulleys placed near the'drlving chain-wheel before the on-run andthe oit-run of the chain.

8. A drawbench comprising a bench-beddingframe in the shape of a soleplate frame oi' box section, a chain supported about both sides of saidvframe in a horizontal plane, at least one gripping carriage, meansincluding said chain for moving this gripping carriage along the sidesof said frame. means for fastening a magndrel` at the sides of the frameof the bench-bedding and means for drawing tubes and for loosening the-tubes from the mandrel which are mounted on the gripping` carriage.

Max ecrnmcx.

